1. Field of the Invention
The present disclosure relates generally to tissue graft fixation and, more particularly, to tissue graft fixation via the use of shape memory polymer material.
2. Related Art
A ligament, such as an anterior cruciate ligament (ACL), that has ruptured and is non-repairable, is generally replaced arthroscopically by a tissue graft. The tissue graft may be harvested from a portion of a patellar tendon having so called “bone blocks” at each end, and from the semitendonosis and gracilis. Alternatively, the tissue graft can be funned from synthetic materials or from a combination of synthetic and natural materials.
The replacement tissue graft is implanted by securing one end of the tissue graft in a socket formed in a passage within the femur, and passing the other end of the graft through a passage formed in the tibia. Generally, sutures arc used to affix each end of the tissue graft to a fastener (e.g., an interference screw or a post), which is then secured to the bone. The use of a fastener, such as an interference screw, may create complications for several reasons: the possibility of the screw threads damaging the grafts during screw installation if the screw is too big in relation to the graft and/or if the space between the passage and the grafts is too small, the graft rotating with the screw during screw installation so that the optimal position of the grafts is lost and/or the grafts are damaged, divergence of the grafts and/or screw occurring, the requirement of a range of fastener sizes for different patients, and, if the screw is non-metal, the possibility of the screw breaking during insertion.